Dopant-mediated structural and magnetic properties of TbMnO3

TL;DR

This study combines computational and experimental methods to explore how doping TbMnO3 with Gd, Dy, and Ho alters its magnetic and structural properties, aiming to enhance magnetoelectric effects in multiferroic materials.

Contribution

It provides new insights into dopant effects on magnetic moments and magnetic ordering stability in TbMnO3, advancing understanding of magnetoelectric coupling mechanisms.

Findings

Dopants increase magnetic moments in TbMnO3.

Dopant substitution stabilizes spiral-spin AFM order.

Enhanced ferromagnetic component observed with doping.

Abstract

Structural and magnetic properties of the doped terbium manganites (Tb,A)MnO3 (A = Gd, Dy and Ho) have been investigated using first-principles calculations and further confirmed by subse- quent experimental studies. Both computational and experimental studies suggest that compared to the parent material, namely, TbMnO3 (with a magnetic moment of 9.7 /muB for Tb3+) Dy- and Ho- ion substituted TbMnO3 results in an increase in the magnetic moment (< 10.6/muB for Dy3+ and Ho3+). The observed spiral-spin AFM order in TbMnO3 is stable with respect to the dopant substitutions, which modify the Mn-O-Mn bond angles and lead to stronger the ferromagnetic component of the magnetic moment. Given the fact that magnetic ordering in TbMnO3 causes the ferroelectricity, this is an important step in the field of the magnetically driven ferroelectricity in the class of magnetoelectric multiferroics, which traditionally have low magnetic moments due to the predominantly antiferromagnetic order. In addition, the present study reveals important insights on the phenomenological coupling mechanism in detail, which is essential in order to design new materials with enhanced magneto-electric effects at higher temperatures.